Storage battery plate assembly



Nov. 16, 1948. c. D. GALLOWAY STORAGE BATTERY PLATE ASSEMBLY OriginalFiled June 3, 1944 F/GZZ.

01 M452 (72/1 EG, 5. Jr a W TIZ Patented Nov. is, 1948 2,454,052

STORAGE BATTEIFY PLATE ASSEMBLY Charles D. Galloway, Wyndmoor, Pa.,aaslgnor to The Electric Storage Battery Company, a corporation of NewJersey I Original application June a, 1944, Serial No.

538,564. Divided and this application December 19, 1944, Serial No.568,787

This invention relates to the manufacture of elements for storagebatteries, and more espe-. cially to the production of an assembly groupof positive or negative plates, united in parallel re-' 2 cum. (or.136-134) 2 on terminal lugs to form an assembly embodying features ofthe invention;

If'ig. 2 is a sectional elevation on the line 22 of Fig. 1 showing alsoa portion of the inverted lation to a common connecting strap, toproduce element; and a novel and improved structure. Figure 3 is adetailed section of the strap and It has been customary to unite theplates of .7 lug portion of a storage battery element embodysuch a groupto the strap by means of lugs proing features of this invention.

.iecting from the upper margins of the plates In the drawing. l0represents the mol l k which lugs are united to the connecting strap ofany suitable material such as cast iron. It is either by inserting theminto slots in the strap provided with open top shallow mold cavities iiand puddiing molten metal by a lead burning and I! of suitable shape anddimensions for castoperation in the spaces between the lugs and the ingthe desired connecting straps. As shown in strap or by first assemblingthe group of plates Fig. 2, the assembled element comprising positiveand there casting the strap around the projecting plates l3, negativeplates llandxinterposed sepalugs in a suitable mold. In either case, inorder o s s located in all inverted Position with to produce anautogenous weld between the lugs the plate lugs l8 and i1 projectingdownwardly and the strap, it has been necessary either to into thecorresponding-mold cavities l l and i2. fuse the lugs and surroundingmetal of the Strap The element'may be held together by any suitas in thepuddling method, or by pouring molten able clamping device (not shown).The element metal into the mold at a sufficiently high temis supportedvertically on a slab i8 of heat-insuperature to melt the lugs, in thecasting method. lating and heat-resisting material such as that Ineither case it is practically impossible to conknown to the trade asTransite" whose upper trol the temperature of the molten metal to avoidsurface is slightly above the upper surface of the softening orpartially fusing the metal of the 2 m p per. As shown in Fig. .the edgesf h lugs below the under surface of the strap, reseparators i5 rest onthis slab and are thus pr suiting in recrystallization of the metal atthese vented from coming into contact with the heated points, thusweakening the lugs where the greatmold. est stresses must be met due tovibration during The mold cavities are provided with downassembiy and inservice. 80 wardly extending conical cavities l9 and 20 for It is anobject of this invention to provide a integrally casting the terminalposts on the straps. group assembly of plates and strap in which thisEjector pins 2| and 22 are shown at the base of defect is eliminated.the post cavities i9 and 20 for removing the It is a further object ofthis invention to procompleted element with attached strap-castings videa group assembly in which the plate lug are from the mold. The ejectorpins may be actuated autogenously welded to the metal of the strap y anysuitable means not shown. only along and near their upper edges butbelow To provide for filling the mold, the gate caviare in intimatemechanical contact with the strap ties 23 and 24, located in gateblocks- 25 and 26, metal without fusion therewith. are shown, throughwhich the molten metal may It is a. further object of the invention toproe p ur d into the mold cavities pr The vide a group assembly in.which the plate lugs gate blocks are here shown as detachable but areautogenously welded to the metal of the may be integral with the moldblock. After the strap only along and near their upper edges while c tngs have solidified, the at s y be out Ofi below, they are grippedbetween the confronting either after the element and strap-castings havesurfaces of the stra by shrinkage pressure withbeen removed from themold or before removal. out fusion. In the latter case, the gate blocks25 and 26 will This application is a division of my copending first beremoved and the gates cut oil in situ by application Serial No. 538,564,filed June 3, 1944, ny suitable means not shown. and is directed to theproduct of the process and Ins rted through and closely fit i intoSuitapparatus described in that application. able openings in the floorof the mold cavities ii The invention will be more clearly understoodand i2 are the super-heating inserts 21 and 28, by referring to oneembodiment thereof described 1 respectively. Since these inserts arealike, the beiowin connection with the accompanying drawone shown at 21will-now be described. It com- 8 in h: prises a block of steel orsimilar heat-conducting Fig. l is a plan view or a mold for castingstraps o5 refractory metal whose upper rectangular face i is flush withthe floor of the mold cavity II and is longitudinally substantiallycoextensive with that cavity. In width, it corresponds with thehorizontal length of the plate lugs l6 and is located immediately belowthe row of these positive plate lugs. The vertical dimensions of theplate lugs l8 as here shown are such as to bring their ends close to butnot actually in contact with the insert 21, leaving a narrow space 29therebetween. Under some conditions, however, it may be satisfactory tobring these plate lugs into actual contact with the insert. Except for ashort distance from its upper surface, the insert 21 is out of contactwith the mold, there being interposed a clearance space 30 to limit thetransfer of heat from the insert to the mold. The insert 21 is providedwith a downwardly extending projection 3| which is surrounded by atubular water-cooled electrical conducting coil 32 adapted to carryhigh-frequency alternating, current for inductively heating the insert21 in the wellknown manner. Standard apparatus for developing andapplying suitable high-frequency current for inductive heating isavailable on the market and it is not deemed necessary to illustrate ordescribe it here.

The insert 21 is provided with a duct 33 through which cooling-liquidmay be circulated and suitably controlled as -by the valve 34.

The operation of the apparatus above described is as follows:

The assembled element, comprising the desired number of positive andnegative plates with interposed separators clamped together in theirfinalrelative positions, is inverted and supported on the mold as'shownin Fig. 2, with the separators resting on the slab i8 and the plate lugsextending into the mold cavities II and I2, with their ends above andclose to or in contact with the upper surfaces of the inserts 21 and 28,respectively. Molten metal, preferably lead-antimony alloy, is thenpoured into the mold cavities H and I2 via the gates 23 and 24 until thecavities are filled to the upper level including the spaces between andbeneath the plate lugs. The temperature of the molten metal is such thatthe plate lugs will not be melted or softened but will retain theirshape or physical identity, as it has been found that such melting orsoftening produces recrystallization or grain growth and weakening ofthe lugs, causing them to break when subjected to stress or vibration inservice. The shrinkage of the molten metal on cooling and solidifying,which occurs as the molten metal contacts the cooler surfaces of thelugs and mold, firmly grips the plate lugs and holds them mechanicallyattached to the straps. However, such mechanical contact between thelugs and the strap does not provide maximum and uniform electricalconductivity to insure minimum voltage drop and equal distribution ofcurrent between the plates when discharging at high rates. Accordingly,the under surface of the strap-casting, formed by the molten metal newaround the plate lugs, as it rests in the mold, together with the tipsof the plate lugs are in a brief period of time raised toan elevatedtemperature to effect a welding or fusing of the lugs to the strap foronly a short distance above the floor of the mold and without melting orfusing the roots or major portion of the lugs. The heat necessary forthe localized welding or fusing of the lugs is applied through thesuper-heating inserts 21 and 28. In the illustrated form of theinvention the shanks of the inserts are surrounded by high-frequencyheating coils 32. High-frequency current is passed through the heatingcoils 22 to heat inductively the inserts 21 and 2B, the intensity andduration of the current being such as to melt the'metal just above theupper surfaces of the inserts and melt the tips of the plate lugs, thuswelding them together for only a short distance, without melting orsoftening the roots or major portion of the lugs gripped mechanically inthe strap-casting. The intensity and duration of the current required toobtain the best results will vary with the dimensions of thestrap-casting and the size and spacing of the plate lugs. With thevolume of current available from standard apparatus for inductiveheating applied to a standard type of storage battery element, a fewseconds has been found adequate to give satisfactory results. As soon asthe current is interrupted, cooling-water is circulated through theducts in'the inserts to prevent further heating effect and also tohasten the cooling, solidification and final shrinkage of the straparound the lug roots.

The length of the mold cavities II and I2 may be made sufilcient toprovide for the maximum width of element. For smaller elements, it isonly necessary to block off the ends of the mold cavities. No otheradjustment is necessary to provide for elements of various numbers orthickness of plates or various plate spacing.

It may be remarked that space is provided above the level of the moltenmetal in the mold and at the roots of the lugs for the access of air,which tends to keep the metal cool at the roots of the lugs and also tokeep the adjacent portions of the separators cool.

It will be noted that there is provided, in accordance with thisinvention, a group of storage battery plates assembled by theirconducting lugs to a suitable connecting strap, wherein the plate lugsat their roots and over the major portion of their length adjacent theplates are mechanically tightly gripped by the adjacent metal of thestrap without being autogenously welded thereto, while the tips of thelugs are autogenously welded to the adjacent metal of the strap, asshown in Fig. 3.

While one convenient form of apparatus for carrying out the process andproducing the product of this invention has been described, includinginductively heated means for applying the superheating temperaturelocally to the tips of the plate lugs and the adjacent metal of thestrap casting, it is not intended to limit the scope of the invention tothis particular apparatus since other means may be employed for applyinglocalized superheating for the selective and localized fusing of the endportions of the lugs to the adjacent metal of the strap.

The described mold for the manufacture of storage batteries is notclaimed since it is the subject matter of my original application SerialNo. 538,564, nor is the described process claimed herein because it isthe subject matter of my I claim:

1. A storage battery element comprising alternately disposed positiveand negative plates with interposed separators, said plates providedwith terminal lugs assembled respectively to positive and negativestraps wherein the roots of the lugs are tightly shrinkage gripped bybut separate from the adjacent metal of the strap and the tips 01. thelugs areautogenously welded to said metal.

2. For a storage battery cell, a group of plates provided with terminallugs assembled to a connecting strap wherein the lugs over a majorportion of their length adjacent the plates are tight- 1y shrinkagegripped by but are separate from the adJacent metal of the strap and thetips of the lugs are autogenously welded to said metal.

CHARLES D. GALIDWAY.

nammvcas ma UNITED STATES PATENTS Number Name Date 911,168 Smith Feb. 2,1909 1,183,810 Gardiner May 18, 1916 1,324,426 London Dec. 9, 19191,811,292 Barhofl June 23, 1931 2,066,691 Lormor Jan. 5, 1937 Ramey May20, 1941

